one thousand, nine hundred and forty-seven
1947
-1
Section::::Abstract.
Chuck Yeager
6185
1947
-1
Section::::Abstract.
Sound barrier
166072
1947
-1
Section::::Design and development.:Research studies.

Bell X-1
208674
1947
-1
Section::::History.:Cold War era.

Rocket-powered aircraft
977522
one thousand nine hundred and forty seven